Wireless network technologies may use sleep mode in order to extend battery life of a wireless device. In sleep mode, a wireless device is powered off but may wake up regularly and briefly to check for paging and to perform any needed handshakes with a wireless network. Within the 2G and 3G wireless standards, dedicated digital channels, that are synchronized between a network and each individual wireless device, are used to enable a wireless device to respond to paging within a desired time constraint. In such networks, the need to respond to paging for time-sensitive applications requires wakeup intervals to be short, e.g., 0.4 second for voice calls. Battery life of a wireless device with one core network technology may be increased from merely one day without sleep mode to about one week with sleep mode.
Many applications which are time-sensitive have a stringent requirement on how fast a wireless device needs to establish active data transfer connection upon being paged. It is also necessary to track the location of a wireless device to the granularity of knowing a base station or an access point.
Wireless access networks are becoming diverse and wireless devices may have more than one multiple interfaces. In addition, these access networks may operate independently, may belong to different operators, or may be loosely coupled. Moreover, base stations or access points using different wireless technologies may not be collocated. A wireless device with multiple interfaces may drain power faster if paging corresponding to the multiple interfaces is handled separately. If two or more wireless interfaces run sleep mode independently but share a common battery source, battery life may be reduced by a factor of 2 or more, which may be unacceptable to some customers.
Therefore, what is needed is a method of paging that may conserve power for a wireless device with multiple radio interfaces corresponding to multiple wireless networks.